Emanuel H. Reporter
	Description • 9 years ago

Two windows at the same time are unusable with x64 build of Nightly 45 on Windows 10 x64.
You can also notice a significant frame rate drop of YouTube videos while typing something into the search bar when using only one window.
With layers.acceleration.disabled=enabled everything works just fine.

I can't reproduce it on x86 build of Firefox (even with same profile) so I guess it's x64 specific.

	Bill McCloskey [inactive unless it's an emergency] (:billm)
	Comment 1 • 9 years ago

Have you tested without e10s enabled?

	Emanuel H. Reporter
	Comment 2 • 9 years ago

My bad, it doesn't seem to be related to e10s.
I can even see this issue on Firefox 42 win64 (release channel) with a completely clean profile.

	Jonas Thiem
	Comment 4 • 9 years ago

As I wrote in #1222821 which is possibly a duplicate, this problem seems to be present on Linux as well. (check out that bug's description for a more detailed description of the experience on my side of this issue)

	Milan Sreckovic [:milan] (needinfo for best results)
	Comment 5 • 8 years ago

CC :benwa, in case it's related to D3D9 performance badness (although, that is E10S only, and this isn't.)

	Martin Best (:mbest)
	Comment 6 • 8 years ago

What's the latest news on this bug?

	Jeff Muizelaar [:jrmuizel]
	Comment 7 • 8 years ago

Is the graphics section of your about:support different in x86 vs x64?

	Emanuel H. Reporter
	Comment 8 • 8 years ago

The issue is still the same on todays nightly.
The graphics section is exactly the same. In fact the only difference on about:support is the user agent string.

	Jeff Muizelaar [:jrmuizel]
	Comment 9 • 8 years ago

(In reply to Emanuel H. from comment #8)
> The issue is still the same on todays nightly.
> The graphics section is exactly the same. In fact the only difference on
> about:support is the user agent string.

Can you post the contents?

	Emanuel H. Reporter
	Comment 10 • 8 years ago

This is the full about:support content from todays nightly 47 (win64 - 20160203)

	Emanuel H. Reporter
	Comment 11 • 8 years ago

I can't reproduce this issue any more. x64 build is working perfectly fine now on all channels and even on the 20160203 nightly (where I definitely could see the issue before).
I think the Geforce driver was at fault.
The last faulty driver I know was 10.18.13.6175. Now I have 10.18.13.6510 installed.
As nobody else had confirmed this issue I'm closing this bug.